University of Oulu

Yli-Halla, M., Lötjönen, T., Kekkonen, J., Virtanen, S., Marttila, H., Liimatainen, M., Saari, M., Mikkola, J., Suomela, R., & Joki-Tokola, E. (2022). Thickness of peat influences the leaching of substances and greenhouse gas emissions from a cultivated organic soil. Science of The Total Environment, 806, 150499.

Thickness of peat influences the leaching of substances and greenhouse gas emissions from a cultivated organic soil

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Author: Yli-Halla, Markku1; Lötjönen, Timo2; Kekkonen, Jarkko2;
Organizations: 1Department of Agricultural Sciences, P.O. Box 56, FI-00014, University of Helsinki, Finland
2Natural Resources Institute, Paavo Havaksen tie 3, FI-90014, University of Oulu, Finland
3Drainage Foundation sr., Simonkatu 12 B 25, FI-00100 Helsinki, Finland
4Water, Energy and Environmental Engineering Research Unit, P.O. Box 8000, FI-90014, University of Oulu, Finland
5Natural Resources Institute, Latokartanonkaari 9, FI-00790 Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3 MB)
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Language: English
Published: Elsevier, 2022
Publish Date: 2022-06-17


The off-site effects of agricultural organic soils include the leaching of N, P, and organic carbon (OC) to watercourses and CO₂, CH₄, and N₂O emissions into the atmosphere. The aim of this study was to quantify how the thickness of organic layers affects these loads. A 19.56-ha experimental field drained by subsurface pipes was established in Ruukki, northwestern Finland. Three plots had a 60–80 cm-thick sedge peat layer and three others had a thickness of 20 cm or less. The drainage pipes lie in mineral soil that, in this field, contains sulfidic material. This study documents the experimental settings and reports on the leaching of substances in the first two years, as well as CO₂, CH₄ and N₂O emissions during eight weeks in one summer. Total N (TN) and OC loads were higher from the thicker peat plots. The mean TN loads during a hydrological year were 15.4 and 9.2 kg ha⁻¹ from the thicker and thinner peat plots, respectively, with organic N representing 36% of TN load. Total P (TP) load averaged 0.27 kg ha⁻¹ yr⁻¹. Dissolved P load represented 63 and 36% of TP in the thicker peat area and only 23 and 13% in the thinner peat area, and was thus increased upon peat thickness. These N and P loads through the subsurface drainage system represented roughly 83% of TN and 64% of TP loads from this field. There were no clear differences in greenhouse gas emissions among the plots during the eight-week monitoring period. Slowly oxidizing sulfide in the subsoil resulted in annual leaching of 147 kg S ha⁻¹, almost ten times that of non-sulfidic soils. Our first results emphasize the effect of the peat thickness on the leaching of substances and warn about considering all organic soils as a single group in environmental assessments.

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Series: Science of the total environment
ISSN: 0048-9697
ISSN-E: 1879-1026
ISSN-L: 0048-9697
Volume: 806
Article number: 150499
DOI: 10.1016/j.scitotenv.2021.150499
Type of Publication: A1 Journal article – refereed
Field of Science: 4111 Agronomy
Funding: The authors thank the Council of Oulu Region for allocating funds originating from the European Regional and Development Fund (ERDF) for the design and implementation of the experimental field. The grants received in 2012–2017 were A32186, A71390 and A71403. We also thank the ERA-NET GAS program which funded the PEATWISE project in 2017–2020 (grant number 4400T-102), Kone Foundation for a financial support in 2018–2022 (grant number 201802192) and Suoviljelysyhdistys ry – Finnish Peat Cultivation Association for financial support in 2019–2021. The authors thank professor Kristiina Regina, Natural Resources Institute Luke, Finland, for organizing the GHG measurement campaign and the respective analyses.
Copyright information: © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (